This invention relates to apparatus for conveying a cylindrical work element toward or away from a machine tool, such as a centerless grinder or the like which prevents the surface of the work from being marred while in transit.
More specifically, this invention relates to a roll conveyor for conducting a relatively heavy cylindrical work element through the work station of a cylindrical grinder or the like wherein the tool acts upon the work to provide the moving force for transporting the work element through the work station. As exemplified in U.S. Pat. No. 2,121,388, most roll conveyors for transporting heavy cylindrical elements generally contain two flights of conveyor rolls that are canted at some fixed angle in regard to the axial center line of a work element seated thereupon. A spiral motion is thus imparted to the work that is determined by the amount of cant provided to the conveyor rolls and the diameter of the work element passing thereover. The linear speed of the work moving along the conveyor is therefore directly related to the angle at which the rolls are set in regard to the axial centerline of the work. For any given set of conditions there can be only one linear speed at which the work can move in true rolling contact with the rolls. If the linear speed were to be changed, as for example by the action of a machine tool upon the work, the work would be caused to slide over the rolls rather than rolling in contact therewith.
Under most operating conditions, the noted sliding action of the work in reference to the conveyor rolls will probably have no noticeable effect. However, in the case of a centerless grinder or the like which is adapted to produce a fine finish upon the work surface, the sliding action generates a discernible score mark upon the work that must generally be removed by a final polishing operation. From an economic standpoint this added machine operation is undesirable.
It should also be noted that most conventional roll conveyors for transporting materials are relatively flat devices which provide little or no lateral stability to the article in transit. These conveyors are thus generally incapable of properly supporting a work element in a machine tool. Under the influence of the tool, the unsupported work generally tends to whip about uncontrollable which adversely affects machining operation.